1. Field of the Invention
The present invention relates to prestressed reinforced concrete railroad ties and the like, and more particularly to methods and apparatus for the manufacturing of prestressed reinforced concrete railroad ties and the like.
2. Description of the Prior Art
Methods and apparatus for the manufacturing of prestressed reinforced concrete railroad ties and the like are known in the prior art.
For example, methods and apparatus for the manufacturing of prestressed reinforced concrete railroad ties are disclosed in U.S. Pat. No. 4,773,840, issued to Steven L. Jantzen on Sep. 27, 1988, and entitled MANUFACTURE OF PRE-STRESSED CONCRETE RAILROAD TIES.
Process and equipment for manufacturing pre-cast elements, made of prestressed concrete, with immediate tensioning, in particular prestressed concrete sleepers are disclosed in Patent Cooperation Treaty Document PCT/EP93/00289.
A method of molding concrete ties or other similar articles having prestressed reinforcing wires or rods therein is disclosed in U.S. Pat. No. 4,051,216, issued to Robert Lyndon Bratchell on Sep. 27, 1977, and entitled IN-LINE MOLDING OF PRESTRESSED CONCRETE ARTICLES.
A portable molding apparatus for prestressed concrete members, such as concrete railroad ties, is disclosed in U.S. Pat. No. 3,577,613, issued to William A Hidden on May 4, 1971, and entitled PORTABLE MOLDING APPARATUS.
An apparatus for forming prestressed concrete products is disclosed in U.S. Pat. No. 3,666,385, issued to Robert S. Baker on May 30, 1972, and entitled APPARATUS FOR MAKING PRESTRESSED CONCRETE MEMBERS.
A PORTABLE TENSIONING SYSTEM FOR PRODUCING PRE-STRESSED CONCRETE BEAMS is disclosed in U.S. Pat. No. 4,149,306, issued to Ralph J. Tice on Apr. 17, 1979.
APPARATUS FOR PRODUCTION OF REINFORCED CONCRETE PRECAST UNITS is disclosed in U.S. Pat. No. 3,491,417, issued to Hans Haller and Erwin Wendl on Jan. 27, 1970.
APPARATUS FOR PRODUCTION OF PRE-STRESSED MOLDED CONCRETE MEMBERS is disclosed in U.S. Pat. No. 3,608,163, issued to Jon W. Harford on Sep. 28, 1971.
Characteristically, some of the above-identified patents and other documents disclose large, complex and extremely expensive equipment, some of which equipment is completely lacking in portability, requires special foundations, or must be located in a specially provided building of large area.
It is believed that the documents listed immediately below contain information which is or might be considered to be material to the examination hereof.
U.S. Pat. No. 3,207,829
U.S. Pat. No. 3,182,948
U.S. Pat. No. 3,999,913
U.S. Pat. No. 3,685,934
British Patent Specification No. 1,357,836
British Patent Specification No. 1,460,149
German Laying Open Document No. 35 43 369
German Patent Publication 1 024 003
Swiss Patent 238960
It is to be understood that the term xe2x80x9cprior artxe2x80x9d as used herein or in any statement made by or on behalf of applicants herein means only that any document or thing referred to as prior art bears, directly or inferentially, a date which is earlier than the effective filing date hereof.
No representation or admission is made that any of the above-listed documents is part of the prior art, or that no more pertinent information exists.
Accordingly, it is an object of the present invention to provide apparatus for the manufacturing of prestressed reinforced concrete railroad ties and the like, which apparatus are simpler and less expensive than apparatuses of the prior art provided for the same purpose.
Another object of the present invention is to provide apparatus for the same purpose which is comprised in part of elements, sometimes called xe2x80x9cpermanent elementsxe2x80x9d, which are fabricated at a manufacturing site, and left at that site, or disposed of near that site when manufacturing operations at that site are permanently or temporarily discontinued.
Yet another object of the present invention is to provide apparatus for the above-stated purpose which is comprised of elements, sometimes called xe2x80x9cportable elementsxe2x80x9d, which are moved from manufacturing site to manufacturing site, and which may be fabricated at a location or locations remote from these manufacturing sites.
A further object of the present invention is to provide paratus for the above-stated purpose, which apparatus is oveground,apparatus, i.e., does not require a foundation.
A further object of the present invention is to provide paratus for the above-stated purpose, which apparatus, during manufacturing, need not be contained in a permanent building, but rather may be contained in a temporary shelter such as a tent, or may in certain climates be operated out of doors.
Another object of the present invention is to provide paratus for the above-stated purpose, which apparatus is equally daptable to the production of one prestressed reinforced concrete railroad tie at a time or to the production of multiple prestressed reinforced concrete railroad ties at a time.
A yet further object of the present invention is to provide apparatus for the above-stated purpose, which apparatus includes means for the provision of a report corresponding to each individual product produced thereby, which report lists the tension n each reinforcing element of the product during the curing of the concrete mass of the product, or the maximum and minimum tension in each reinforcing element of the product during the curing of the concrete mass of the product.
Another object of the present invention is to provide apparatus for the above-stated purpose wherein each reinforcing element incorporated into each product is individually fully tensioned.
Yet another object of the present invention is to provide apparatus for the above-stated purpose which minimizes wastage of reinforcing element material.
A further object of the present invention is to provide apparatus for the above-stated purpose, which apparatus can readily be adapted to the production of reinforced concrete elements of many different kinds, sizes and configurations.
A yet further object of the present invention is to provide apparatus for the above-stated purpose, which apparatus can readily be adapted to manufacture in existing buildings.
Another object of the present invention is to provide novel methods for fabricating apparatuses for the manufacture of prestressed reinforced concrete railroad ties and the like.
Yet another object of the present invention is to provide novel methods for the manufacture of prestressed reinforced concrete railroad ties and the like.
A further object of the present invention is to provide methods of accomplishing the above-stated objects, which methods include the step of fully tensioning each reinforcing element in a particular product individually.
A yet further object of the present invention is to provide methods of accomplishing the above-stated objects, which methods include the steps of individually monitoring the tension in each reinforcing element during the curing of a particular product and providing a certificate setting forth the tension in each individual reinforcing element during the curing of a particular product.
Another object of the present invention is to provide methods of accomplishing the above-stated objects, which methods include the step of providing a certificate corresponding to each particular product in which is tabulated the maximum and minimum tension in each reinforcing element of that product throughout the curing of that product.
Other objects of the present invention will in part be obvious and will in part appear hereinafter.
The present invention, accordingly, comprises the several steps and the relation of one or more of such steps, with respect to each of the others, and the apparatus embodying features of construction, combinations of elements, and arrangements of parts which are adapted to effect such steps, all as exemplified in the following disclosure, and the scope of the present invention will be indicated in the claims appended hereto.
In accordance with a principal feature of the present invention an apparatus for the manufacturing of prestressed reinforced concrete railroad ties is comprised of an elongated spine member which is formed substantially entirely of concrete and has no foundation.
In accordance with another principal feature of the present invention said spine member, in a preferred embodiment of the present invention, is composed of a plurality of mutually abutting modules, each of which modules is formed substantially entirely from concrete.
In accordance with yet another principal feature of the present invention said spine member, in another preferred embodiment of the present invention, is a single, monolithic body of concrete.
In accordance with a further principal feature of the present invention said spine member, in yet another preferred embodiment of the present invention, is provided at its opposite ends with abutment frame means which are deeply embedded in the concrete of said spine member and which include abutment portions which project from the upper surface of the concrete of said spine member and are adapted to support anchor receiving means to which reinforcing wires can be anchored.
In accordance with a yet further principal feature of the present invention said spine member is provided with mold alignment guides which are affixed to its top surface.
In accordance with another principal feature of the present invention at least one end of each of said reinforcing wires is anchored to one of said anchor receiving means by anchoring means, which anchoring means includes a threaded rod passing through a hole in said anchor receiving means and a nut engaged with said threaded rod for adjusting the tension in its associated reinforcing wire.
In accordance with yet another principal feature of the present invention each of said anchoring means includes an intermediate body interposed between said threaded rod and said reinforcing wire, and a strain gauge coupled to said intermediate body for use in measuring the tension in said reinforcing wire.
In accordance with another principal feature of the present invention a bulbous protrusion or button is attached to an end of said reinforcing wire and said anchoring means includes coupling means which is adapted to receive said end of said reinforcing wire and to prevent said protrusion from escaping from said coupling means.
In accordance with a yet further principal feature of the present invention the spine member of a balanced compression embodiment of the present invention is provided with elevating means for elevating it above the surface by which it is supported, said elevating means defining, with said spine member, a passage which extends beneath said spine member and substantially from end to end thereof.
In accordance with another principal feature of the present invention said balanced compression embodiment of the present invention further includes first and second bridge means each of which confronts one end of said spine member, projects above the upper surface of said spine member, and confronts said passage.
In accordance with yet another principal feature of the present invention at least one tension resisting member extends from end to end of said passage and is affixed to the lower ends of said bridge means.
In accordance with a further principal feature of the present invention the upper ends of said bridge means are provided with anchor receiving means whereby the opposite ends of reinforcing wires can be anchored to said bridge means.
In accordance with a yet further principal feature of the present invention the anchoring means attached to one of said anchor receiving means comprises strain gauge means.
In accordance with another principal feature of the present invention rails are provided on each side of said spine member, which rails are adapted to support a straddle truck straddling said spine member.
In accordance with yet another principal feature of the present invention mold raising means are provided whereby the mold or molds carried by said spine member can be raised from and lowered to the upper surface of said spine member.
In accordance with a further principal feature of the present invention certain preferred embodiments thereof include computer means and printer means associated with all of the strain gauges incorporated in said anchoring means and adapted to provide printed reports of the tension in each of the reinforcing wires of a set of reinforcing wires simultaneously mounted on the device of said preferred embodiment.
In accordance with a yet further principal feature of the present invention a method of manufacturing prestressed reinforced concrete railroad ties comprises the steps of tensioning a set of reinforcing wires between the ends of a single, aboveground spine member, and individually adjusting the tension in each such reinforcing wire.
In accordance with another principal feature of the present invention said method of manufacturing prestressed reinforced concrete railroad ties includes the step of printing a tabulation of the tension in each individual reinforcing wire as measured by strain gauges incorporated in one of the anchoring means associated with each reinforcing wire.
For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings.